Crate browser_crypto

A safe Rust interface to browser-based cryptographic operations using the Web Crypto API.

This crate provides a type-safe wrapper around the browser’s native cryptographic functionality, making it easier to perform common cryptographic operations in WebAssembly applications.

Features

• Type-safe cryptographic algorithm implementations
• Secure nonce generation and handling
• AES-256-GCM encryption and decryption
• Proper error handling and conversion from Web API exceptions

Examples

use browser_crypto::aes256gcm::Aes256Gcm;
use browser_crypto::algorithm::Algorithm;

async fn encrypt_data() -> Result<(), Box<dyn std::error::Error>> {
    // Create a new AES-256-GCM instance with a key
    let key_bytes = [0u8; 32]; // Replace with your secure key
    let cipher = Aes256Gcm::from_key(&key_bytes).await?;

    // Generate a random nonce
    let nonce = Aes256Gcm::generate_nonce()?;

    // Encrypt some data
    let data = b"Secret message";
    let encrypted = cipher.encrypt(&nonce, data).await?;

    // Decrypt the data
    let decrypted = cipher.decrypt(&nonce, &encrypted).await?;
    assert_eq!(data.to_vec(), decrypted);

    Ok(())
}

Security Considerations

This crate relies on the browser’s implementation of the Web Crypto API, which:

• Uses the platform’s secure random number generator
• Implements cryptographic operations in native code
• Provides protection against timing attacks
• Follows modern cryptographic standards

However, users should be aware that:

• Keys should be generated and stored securely
• Nonces should never be reused with the same key
• The security of the application depends on the security of the browser

Features Flags

• log-error: Enables console logging of unknown errors (useful for debugging)

Browser Compatibility

This crate requires a browser with support for:

• Web Crypto API
• WebAssembly
• Async/await

Most modern browsers (Chrome, Firefox, Safari, Edge) support these features.

Error Handling

The crate provides detailed error types that map directly to Web Crypto API exceptions, making it easier to handle and debug cryptographic operations:

• Error: General Web Crypto API errors
• EncryptionError: Encryption-specific errors
• DecryptionError: Decryption-specific errors
• NonceError: Nonce generation and validation errors
• ImportKeyError: Key import and format errors

Implementation Details

This crate uses wasm-bindgen to interface with the Web Crypto API and provides a safe Rust interface for:

• Key management
• Nonce generation
• Encryption/decryption operations
• Error handling and conversion

The implementation focuses on safety, correctness, and ergonomic use in Rust while maintaining the security properties of the underlying Web Crypto API.

Modules

aes256gcm

AES-256-GCM encryption implementation

algorithm

Enums

Error

General errors that can occur when interacting with the Web Crypto API.